Effect of Bose--Einstein statistics on multiplicity distributions and correlations in multiparticle production processes at high energies

It is shown that only a small number of elementary cells in phase space are populated in a multiparticle production reaction even at high energy (> 100 GeV), leading to occupancy numbers for identical bosons in individual cells which are not small. It follows that quantum-statistical fluctuations are of significant magnitude. The effects on multiplicity distributions and integral correlation functions of π mesons produced in high-energy interactions are derived. Comparison with experimental results at incident energies above 100 GeV indicates that Bose-Einstein fluctuations may be a principal source of broadening of the multiplicity distribution and of positive short-range correlations among identical particles. The effect is nondynamical and nonkinematical in the usual sense, but is due to identical-particle symmetry, and is the counterpart of the Hanbury Brown-Twiss effect in the electromagnetic field.